Chassis with raising box structure to anchor passenger seats

ABSTRACT

A motor vehicle chassis including a rear central cross member, a hollow beam positioned over the rear central cross member along this rear central cross member, and a floor seat-cushion support part including rear seat fittings, supported at the rear by the hollow beam positioned under the seat-cushion support part. The beam includes a rear raiser including a horizontal plate fixed to the rear central cross member and further includes a blanking sheet fixed to the horizontal plate of the rear raiser and including at least one anchoring reinforcement assembled on the inside of the hollow beam. The reinforcement, which forms a hollow box section, connects the rear raiser and the blanking sheet, an upper face of the anchoring reinforcement supports a connecting piece, the connecting piece also being assembled, on the outside of the hollow beam, with the rear raiser.

The invention relates to the field of motor vehicle chassis, inparticular electrically-driven or hybrid vehicles. In order to providesufficient autonomy to the electrically-driven or hybrid vehicles,accumulator batteries have to be fitted. The volume of said batteries issubstantially greater than that occupied by a conventional energystorage tank, such as for example a fuel tank.

One solution consists in making use of a defined volume below thepassenger seats, by modifying the profile of the floor so as to isolatesaid volume from the passenger compartment. The passenger seats thusdirectly rest on a raised area of the floor. The height of the seats isable to be the same as the height of the seats in vehicles in the samerange, designed to be driven by an internal combustion engine, or may behigher.

The patent application JP 07 156 826 thus discloses a chassis structurefor an electrically-driven motor vehicle, in which a volume below thefront and rear passenger seats is reserved for the battery by separatingsaid volume from the passenger compartment. Vertical raising plates arepositioned to the front and to the rear of the seats. A raised floorseat-cushion area extends from front to rear between said verticalraising plates, and extends laterally between the lateral raisingsupports fixed to the lateral side portions of the bodywork.

Such a structure is not applicable to a three-door vehicle since it isnecessary for the rear passenger seats to be bounded by fixed bodyworkside portions, to which the lateral raising supports are assembled.

Moreover, where it is desired to provide the same vehicle as anelectrically-driven model and as a model driven by an internalcombustion engine, the line of the welding points, which make itpossible to assemble the floor elements to the longitudinal members ofthe vehicle, may not have the same geometry for the electric vehicle andfor the vehicle driven by an internal combustion engine. Thus, for theproduction of the two vehicles, it is necessary to put in position twoseparate welding lines, which increases both the development andproduction costs.

Finally, by raising the seat-cushion area of the seats, it is necessaryto displace the rear seat fittings and the anchoring point of theassociated seat belts. Said fittings and said anchoring points areconventionally attached to a rear supporting crossmember. When raisingthe seat cushions, the tendency is thus to displace the fittings and theanchoring points to an attached raising structure which, in order torespect maximum weight limitations, is generally less rigid than therear crossmember.

The object of the invention is to propose a chassis geometry for anelectric vehicle or for a further vehicle requiring an increased volumeof the energy storage tank, which makes it possible to produce at thesame time electrically-driven vehicles and vehicles driven by aninternal combustion engine, using a large number of components andcommon production methods.

The object of the invention is also to propose a chassis structurehaving a raised floor, making it possible to attach the seat fittingsand the anchoring points of the seat belts in a secure manner.

To this end, a motor vehicle chassis comprises a rear centralcrossmember. It also comprises a floor seat-cushion support partprovided with rear seat fittings and supported to the rear by the rearcentral crossmember. The chassis further comprises a hollow beamarranged above the rear central crossmember along said rear centralcrossmember, said beam comprising a rear raising part. The rear raisingpart may comprise a vertical raising plate and a horizontal plate fixedto the rear central crossmember, the vertical plate and the horizontalplate being, for example, produced from the same metal sheet, foldedalong an edge common to the two plates. The hollow beam comprises ablanking sheet fixed in turn to the horizontal plate, and comprises atleast one anchoring reinforcement assembled inside the hollow beam, thereinforcement forming a hollow box structure and connecting the rearraising part and the blanking sheet. An upper face of the anchoringreinforcement supports a mounting part, said mounting part also beingable to be assembled, on the outside of the hollow beam, to the rearraising part, for example to the vertical plate of the rear raisingpart.

Preferably, the anchoring reinforcement connects a vertical plate of therear raising part and a part of the blanking sheet, which in turn isalso vertical. The anchoring reinforcement may also be fixed to thehorizontal plate of the rear raising part.

According to a preferred embodiment, one face of the anchoringreinforcement is made flush in the vicinity of the seat-cushion supportpart of the floor.

Advantageously, the hollow box structure is delimited by a face formingpart of the blanking sheet, by two faces forming part of the rearraising part and by three faces formed by a sheet folded in a U-shapeassembled inside the hollow beam.

A rear seat fitting may be anchored to a mounting part fixed to theanchoring reinforcement.

Preferably, the chassis comprises at least two anchoring reinforcementsand anchoring parts for seat belts are anchored to the mounting parts.

The distance between the centers of the two box structures may range,for example, between 30 cm and 60 cm.

According to a preferred embodiment, each mounting part comprises ahollow volume assembled to the external face of the vertical plate ofthe rear raising part and is extended by a planar bearing surfaceassembled to a rear part of the seat-cushion support in the region ofthe anchoring reinforcement. (The external face denotes in this case theexternal face of the hollow beam).

The blanking sheet comprises, for example, a vertical surface parallelto the vertical plate of the rear raising part and may also comprise twolateral vertical surfaces folded back from said vertical surface andassembled to the rear vertical raising plate, along the sides thereof.

According to a preferred embodiment, the chassis comprises twolongitudinal members connected by the rear central crossmember andcovered at the front of the crossmember by lateral floor reinforcements.A transverse reinforcement and two lateral raising parts are fixed tosaid lateral reinforcements. The seat-cushion support part of the flooris fixed above the two lateral raising parts, the aforementioned rearraising part and the transverse reinforcement so as to create a housingfor an energy storage tank below the seat-cushion support part of thefloor.

Advantageously a strip-shaped portion of the horizontal plate of therear raising part protrudes beyond the rear of the vehicle relative tothe blanking sheet and relative to the rear central crossmember. Thus,it is possible to fix a rear floor plate to the rear of the twolongitudinal members and to the rear edge of the rear raising part bywelding just two thicknesses of metal sheet.

Advantageously, the rear raising part and the transverse reinforcementextend solely between the internal sides of the two lateral floorreinforcements. The walls defining the volume dedicated to the energystorage tank are thus independent of the external bodywork and theapertures of the vehicle.

The present invention will be understood more clearly by reading thedetailed description of several embodiments taken by way of non-limitingexample, and illustrated by the accompanying drawings, in which:

FIG. 1 is a schematic perspective view in partial section along I-I ofFIG. 3 of a chassis portion according to the invention,

FIG. 2 is a schematic perspective view of several constituent elementsof the chassis of FIG. 1,

FIG. 3 is a schematic perspective view of several further constituentelements of the chassis of FIG. 1,

FIG. 4 is an exploded perspective view of a rear preassembled part ofthe chassis of FIGS. 1 to 3.

It will be noted that the respective proportions of the schematic viewsof the different figures do not necessarily correspond, said schematicviews solely having the purpose of illustrating certain features of theinvention.

The arrow 44 on each occasion in FIGS. 1 to 4 indicates the forwarddirection of the vehicle (not shown).

As illustrated in FIG. 1, a chassis 1 comprises a floor seat-cushionsupport part 21 to which a bench 55 for a rear passenger seat isassembled. To the rear of the seat bench 55, the seat-cushion supportpart 21 is supported by a rear central crossmember 3 connecting twolongitudinal members 2 of the vehicle (not shown). The rear centralcrossmember 3 is a beam of U-shaped section, the U-shaped section beingopen at the top and laterally bounded by two horizontal edges 54 a and54 b. The depth of the U-shaped section may be uniform or variable butsuch that its two edges 54 a and 54 b remain planar.

According to the invention, a hollow beam 33 is arranged above the rearcrossmember 3, to which it is assembled by welding along the edges 54 a,54 b. Said hollow beam 33 supports a rear part 30 of the seat-cushionsupport part 21 of the floor. The walls of the hollow beam 33 consist ofa rear raising part 14, a blanking sheet 25 and the rear part 30. Saidthree sheet parts are welded together along welding lines transverse tothe vehicle. A first sheet is the horizontal rear part 30 of theseat-cushion support part 21. The two other sheets, assembled to thefirst, are:

a rear raising part 14, consisting of a metal sheet folded so as to forma vertical plate 19 placed substantially above the horizontal edge 54 aof the rear crossmember 3, and a horizontal plate 18 welded to the rearcrossmember 3 along the edges 54 a and 54 b; the rear raising part 14comprises an upper horizontal edge 20, along which it is assembled bywelding below the rear part 30 of the seat-cushion support area 21,spaced apart from the rear end of said seat-cushion support area;

a blanking sheet 25 comprising a vertical surface 28, arranged inparallel to the plate 19, substantially above the edge 54 b of the rearcrossmember 3 and assembled by welding along its upper edge 26 to avertical end edge 27 of the rear part 30 of the seat-cushion supportpart 21. The blanking sheet 25 comprises a lower horizontal edge 43turned outward from the hollow beam 33, i.e. toward the rear of thevehicle. Via the edge 43, the blanking sheet 25 is assembled by weldingin three thicknesses, both to the horizontal plate 18 of the rearraising part 14 and to the edge 54 b of the rear crossmember 3.

The upper face of the hollow beam 33 is closed by the horizontal rearpart 30 of the seat-cushion support part 21. Said rear part 30 isassembled by at least one welding line along the edge 20 of the rearraising sheet 14 and by a parallel welding line along the end edge 27 ofthe rear part 30.

The horizontal plate 18 of the rear raising part 14 protrudes to therear of the vehicle relative to the edge 43 of the blanking sheet 25 andprotrudes relative to the edge 54 b of the rear central crossmember 3. Arear strip 47 of the horizontal plate 18 is thus available to besuperposed with a front edge of a rear floor plate 6 (as seen in FIG. 2)and to be assembled by welding to said rear floor plate 6.

Two anchoring reinforcements 24 (only one being shown in FIG. 1) areassembled inside the hollow beam 33 in the form of a box structure, thevertical walls 48 thereof each extending over the entire height and overthe entire width (i.e. in the front-to-rear direction of the vehicle) ofthe internal cross section of the hollow beam 33. In the region of theupper face 49 of each reinforcement 24 is assembled a mounting part 53visible in FIGS. 1 and 3, to which seat fittings (not shown) andanchoring parts (not shown) of seat belts 52 are assembled. Thus a rigidconnection is obtained of the mounting parts 53, capable of withstandingthe forces able to be exerted on the parts 53 in the event of afront-end or rear-end collision of the vehicle, said forces beingtransmitted to the rear central crossmember 3 via said rigid assembly.

Preferably, for a vehicle having three rear passenger seats, the hollowbeam 33 may comprise two anchoring reinforcements 24, so as to be ableto attach to each of said reinforcements the anchoring parts of the seatbelts of a central seat and a side seat. It goes without saying that adifferent number of anchoring reinforcements could be envisaged, forexample a single central reinforcement, in particular in the case of avehicle only providing two rear passenger seats, or three reinforcementsor four reinforcements, some of the reinforcements thus not being usedto fix the seat belt anchoring parts.

FIG. 2 is a perspective view of a front part of the hollow beam 33,assembled to the rear central crossmember 3. Elements common to FIG. 1are seen in FIG. 2, the same elements thus being denoted by the samereference numerals. The rear raising sheet 14 may be seen in particularin FIG. 2, said rear raising sheet comprising the vertical plate 19 andthe horizontal plate 18 assembled to the rear central crossmember 3along the edges 54 a and 54 b of the crossmember 3.

It should be noted that the assembly between the rear raising part 14and the rear central crossmember 3, in addition to the assembliesbetween the other sheets of the chassis, may be preferably carried outby spot welding, or following a continuous line, or following any otherassembly procedure, for example by adhesive bonding or riveting.

The vertical plate 19 is extended along its upper edge by the horizontaledge 20 making it possible to assemble it by welding to the rear part 30of the seat-cushion support part 21. The vertical plate 19 is alsoextended along its vertical edges by two edges 42 folded back toward thefront of the vehicle, so as to be located in a plane parallel to thelongitudinal axis of the vehicle.

The horizontal plate 18 protrudes beyond the edge 54 b of the rearcentral crossmember 3. Thus, it is possible to superpose a front end 6 aof the rear floor plate 6 at the rear of the horizontal plate 18,without this interfering with the thickness of the edge 54 b of the rearcentral crossmember 3. A double-thickness weld is thus possible betweenthe horizontal plate 18 and the rear floor plate 6.

The two box structures for the anchoring reinforcements 24 are assembledwithin the dihedron formed by the vertical plate 19 and the horizontalplate 18, the mutual spacing thereof substantially corresponding to thespacing between two anchoring points for seat belts for rear passengersof the vehicle. Each anchoring reinforcement 24 is obtained byassembling a sheet 50 folded back so as to comprise three flaps arrangedin a U-shape, inside the dihedron formed by the rear raising part 14.The sheet 50 is positioned so that the bottom face 49 of the U-shapeconnects the upper edges of the vertical plate 19 of the rear raisingpart 14 and the vertical surface 28 of the blanking sheet 25 (FIGS. 1and 3).

The ends of the sheet 50 opposing the face 49 of the U-shape areassembled to the horizontal plate 18 of the rear raising part 14. Thefour vertical edges of the vertical walls 48 of the U-shape areassembled either to the vertical plate 19 or to the vertical surface 28visible in FIGS. 1 and 3. Thus anchoring reinforcements 24 are obtainedin the form of box structures consisting of three faces of a sheet 50, avertical plate portion 19 of the rear raising part 14, a horizontalplate portion 18 of the rear raising part and a vertical surface portion28 of the blanking sheet 25 (visible in FIGS. 1 and 3). The reinforcingbox structures 24, in the form of a rigid parallelepiped shape,effectively resist torsional deformation both in a horizontal plane andin any vertical plane.

The assembly of the vertical walls 48 of the sheets 50 may be carriedout by means of assembly strips 51 perpendicular to the walls 48,obtained either by folding or by crimping the sheet 50. A preferredembodiment consists in obtaining assembly strips 51 by crimping thesheet 50 so that each wall 48 is extended along three consecutive sidesby the same assembly strip 51, which further improves the rigidity ofthe final assembly.

FIG. 3 is a further view in perspective of the hollow beam 33 of FIGS. 1and 2, before assembly of the seat-cushion support area 21. FIG. 3 makesit possible to see more accurately the mounting parts 53 of FIG. 1, inaddition to certain details of the blanking sheet 25. It will be notedthat the mounting parts 53 are, in reality, attached to the seat-cushionsupport part 21, not shown in FIG. 3. FIG. 3 thus enables just thepositions of said mounting parts 53 to be visualized relative to the boxstructures of the anchoring reinforcements 24. Elements common to FIGS.1 and 2 are found in FIG. 3, the same elements thus being denoted by thesame reference numerals. FIG. 3 shows, in particular, the arrangementbetween the rear raising part 14, the anchoring reinforcements 24 andthe rear blanking sheet 25 in addition to the position of the mountingparts 53.

The blanking sheet 25 is welded by its vertical surface 28 to theassembly strips 51 of the reinforcements 24 (FIG. 2). The verticalsurface 28 has a lower horizontal edge 43 which is assembled by weldingin three thicknesses to the horizontal plate 18 of the rear raising part14 and to the edge 54 b of the rear central crossmember 3, so as topermit a strip 47 of the horizontal plate 18 to protrude to the rearrelative to the two further thicknesses of the sheets to which it isassembled. Lateral vertical surfaces 29, extending the vertical surface28 of the blanking sheet but folded back in a plane parallel to thelongitudinal axis of the vehicle, close the hollow beam 33 on thelateral sides thereof. Said surfaces 29 are assembled to the verticaledges 42 of the rear raising part 14 (visible in FIG. 2).

The upper edges of the vertical surfaces 29 and 28 of the blanking sheet25 respectively have edges 31 and 26 serving as welding strips and whichmay either be folded back horizontally or remain vertical. Preferably,the lateral edges 31 are folded back horizontally so as to be weldedbelow the seat-cushion support part 21 and the upper edge 26 remainsvertical so as to be welded to the rear end of the seat-cushion supportpart 21. Other configurations of edges, for assembly by welding, maynaturally also be envisaged. For example, the lateral edges 31 may bereplaced by vertical strips extending downwardly from the sides of therear part 30 of the seat-cushion support part 21 visible in FIG. 4.

A mounting part 53 is assembled to the seat-cushion support part 21 inthe region of each of the reinforcements 24. Each mounting part 53comprises an upper plate forming a planar part 45 placed in the regionof an upper face 49 of one of the reinforcements 24 above the horizontaledge 20 of the rear raising part 14. Each upper plate 45 is fixed to ahollow body 46 arranged therebelow, welded to the front face of thevertical plate 19 of the rear raising part 14.

Each mounting part 53 bears against the upper face of the rear part 30of the seat-cushion support part 21 (see FIG. 4) which is assembled tothe top of the hollow beam 33.

The seat fittings and the anchoring parts of the seat belts 52 (visiblein FIG. 1) are assembled to a proportion of the mounting parts 53located in front of the hollow beam 33. The anchoring reinforcements 24serve to stiffen the hollow beam 33 in order to improve the rigidity ofthe seat-cushion support part 21. Said anchoring reinforcements 24 alsoprovide a particularly strong attachment point for anchoring seat belts,or for the assembly of mounting brackets for passenger seats.

The mounting parts 53 displaced to the front of the hollow beam 33 makeit possible to arrange anchoring points sufficiently far forward alongthe longitudinal axis of the vehicle, relative to the seat bench 55(visible in FIG. 1). The rigid assembly of the hollow bodies 46 and thehollow beam 33 further improves the overall rigidity of the hollow beam33.

FIG. 4 is an exploded perspective view of a rear central part of achassis according to the invention. Elements common to the precedingfigures are seen in FIG. 4, the same elements thus being denoted by thesame reference numerals. As illustrated in FIG. 4, the chassis 1comprises two longitudinal members 2 connected by the rear centralcrossmember 3 to which the hollow beam 33 is assembled. The rear floorplate 6 is assembled to the upper part of the longitudinal members 2located to the rear of the crossmember 3.

Said rear floor plate 6 is also assembled to the hollow beam 33 so as tocome in line with the base of said beam 33, in the vicinity of the edge54 b of the beam 3 (see FIG. 2). To the front of the rear centralcrossmember 3, the longitudinal members 2 each support a lateral floorreinforcement 4 on their upper part. The lateral floor reinforcements 4each consist of a sheet crimped in a central direction close to thehorizontal, extending between an external edge and an internal edge ofthe corresponding longitudinal member 4. The external edge of eachlateral reinforcement 4 is assembled to the external edge of thecorresponding longitudinal member. The internal side 7 of each lateralfloor reinforcement 4 is assembled, by a weld line connecting threethicknesses of sheet, to the internal edge of the longitudinal member,and to a lower edge of a lateral raising part 13 consisting of a sheetportion in a substantially vertical direction.

A transverse reinforcement 5 connects the lateral floor reinforcements 4at the front and spaced apart from the rear central crossmember 3. Thetransverse reinforcement 5 is in the form of a crimped sheet, in asubstantially vertical direction and transverse to the axis of thevehicle. A passage 8 is formed in the lower central part in saidtransverse reinforcement 5. The height of the transverse reinforcement 5is such that the upper edge 11 of the transverse reinforcement 5 may belocated, in the assembled position of the chassis, substantially at thesame height as the open upper face of the hollow beam 33. The transversereinforcement 5 and the hollow beam 33 are connected along each lateralfloor reinforcement 4 by lateral raising parts 13 arranged on each side.

The upper edge 17 of each lateral raising part 13 joins, at each of itsends, the upper edge 11 of the transverse reinforcement 5 and the upperface of the hollow beam 33. Between said ends, the upper edge 17 of eachlateral raising part 13 has a slight concavity. The transversereinforcement 5, the lateral raising parts 13 and the vertical plate 19of the rear raising part 14 thus delimit a housing 34 which may beclosed at the top by the seat-cushion support part 21 of the floor. Theseat-cushion support part 21 of the floor is assembled by its peripheryto the upper edge 11 of the transverse reinforcement 5 and to the upperedges 17 of the lateral raising parts 13, and by the periphery of itsrear part 30 provided with mounting parts 53, to the edges 20, 26 and 31of the hollow beam 33 which form welding strips. As the housing 34 isthus isolated from the passenger compartment, it is available forreceiving an energy storage tank. The seat-cushion support part 21 ofthe floor comprises, apart from the rear part 30 closing the hollow beam33 and a cover-forming portion 23 closing the upper part of the housing34, a front plate 22 which is folded back downwards from the cover 23.The front plate 22 is capable of covering the transverse reinforcement 5and comprises a passage area 9 designed to nest on the passage 8 of thetransverse reinforcement 5. The cover portion 23 has an upwardlyoriented concavity, with an axial reinforcement beam 23 a. Planar areas23 b are provided on the cover portion 23 in the vicinity of the rearpart 30, for the assembly of the mounting parts 53 shown in the explodedposition in FIG. 4 to the seat-cushion support part 21.

By the arrangement disclosed in FIGS. 1 to 4, a housing 34 is madeavailable below the rear passenger seats in which an energy storage tanksuch as a set of accumulator batteries or a pressurized fuel tank may bearranged. The proposed structure makes it possible to obtain a structuresupporting the seats, independent of the lateral edges of the bodywork,and thus is suitable both for a three-door vehicle and for a five-doorvehicle.

The association of the hollow beam 33 with the rear central crossmember3 which is assembled there in a rigid manner makes it possible to obtaina transverse beam structure having an increased modulus of flexibility,with low material consumption. The addition of reinforcing boxstructures 24 improves the torsional stiffness of the beam and, withoutconsuming additional material, contributes to providing particularlystrong anchoring points for the seat attachment fittings and for theanchoring parts of the seat belts.

1-10. (canceled)
 11. A motor vehicle chassis comprising: a rear centralcrossmember; a hollow beam arranged above the rear central crossmemberalong the rear central crossmember; and a floor seat-cushion supportpart including rear seat fittings, supported to a rear by the hollowbeam positioned under the seat-cushion support part; the beam comprisinga rear raising part comprising a horizontal plate fixed to the rearcentral crossmember; the beam further comprising a blanking sheet fixedto the horizontal plate of the rear raising part and comprising at leastone anchoring reinforcement assembled inside the hollow beam, thereinforcement forming a hollow box structure connecting the rear raisingpart and the blanking sheet, an upper face of the anchoringreinforcement supporting a mounting part, the mounting part being alsoassembled on an outside of the hollow beam to the rear raising part. 12.The motor vehicle chassis as claimed in claim 11, wherein the upper faceof the anchoring reinforcement is made flush in a vicinity of theseat-cushion support part of a floor.
 13. The motor vehicle chassis asclaimed in claim 12, wherein the hollow beam is delimited by a faceforming part of the blanking sheet, by two faces forming part of therear raising part, and by three faces formed by a sheet folded in aU-shape assembled inside the hollow beam.
 14. The motor vehicle chassisas claimed in claim 11, wherein a rear seat fitting is anchored to amounting part fixed to the anchoring reinforcement.
 15. The motorvehicle chassis as claimed in claim 14, comprising at least twoanchoring reinforcements, and wherein anchoring parts for seat belts areanchored to the mounting parts.
 16. The motor vehicle chassis as claimedin claim 11, each mounting part comprising a hollow volume assembled toan external face of the rear raising part and extended by a planarbearing surface assembled to a rear part of the seat-cushion supportpart in a region of the anchoring reinforcement.
 17. The motor vehiclechassis as claimed in claim 11, wherein the blanking sheet comprises avertical surface parallel to a vertical plate of the rear raising part,and two lateral vertical surfaces folded back from the vertical surfaceand assembled to the vertical plate of the rear raising part, alongsides thereof.
 18. The motor vehicle chassis as claimed in claim 11,comprising two longitudinal members connected by the rear centralcrossmember and covered at a front of the crossmember by lateral floorreinforcements, a transverse reinforcement being fixed to the lateralreinforcements and two lateral raising parts being fixed to the lateralreinforcements, the seat-cushion support part of a floor being fixedabove the two lateral raising parts, the rear raising part and thetransverse reinforcement so as to create a housing for an energy storagetank below the seat-cushion support part of the floor.
 19. The motorvehicle chassis as claimed in claim 18, wherein a strip of thehorizontal plate of the rear raising part protrudes beyond a rear of thevehicle relative to the blanking sheet and relative to the rear centralcrossmember.
 20. The motor vehicle chassis as claimed in claim 19,wherein the rear raising part and the transverse reinforcement extendsolely between internal sides of the two lateral floor reinforcements.